Venture cars can no longer be used for boarding/deboarding

[Trogdor]

That being said I think the cars delivered so far are individual cars instead of solid train sets?

Not solid trainsets, but some of the cars in service are married pairs. I was in one such pair about a week ago.

Imagine a train car where you have to use the vestibule area of an adjoining car for access

You mean like Amfleet IIs and Viewliners?